Demo generate a CPU profile.

Makefile

@@ -69,6 +69,7 @@ dirs = 	testppack \
 	rangecopy \
 	ranges \
 	recover \
+	runpprof \
 	shax \
 	shifter \
 	show64 \

runpprof/runpprof.go

@@ -0,0 +1,43 @@
+/*
+Demo generating a CPU profile.
+*/
+package main
+
+import (
+	"fmt"
+	"os"
+	"runtime/pprof"
+	"time"
+)
+
+func runner() {
+	for i := 0; i < 1000000000; i++ {
+		for j := 0; j < 30; j++ { //
+			_ = i + j
+		}
+	}
+}
+
+func main() {
+	s := time.Now()
+	fmt.Println("Start", s)
+	//
+	f, err := os.Create("./cpu.prof")
+	if err != nil {
+		panic(err)
+	}
+	err = pprof.StartCPUProfile(f)
+	if err != nil {
+		panic(err)
+	}
+	runner()
+	pprof.StopCPUProfile()
+	//
+	err = f.Close()
+	if err != nil {
+		panic(err)
+	}
+	e := time.Now()
+	fmt.Println("End", s)
+	fmt.Println("Elapsed", e.Sub(s))
+}